/**
 *
 * Show multicast messages for some group on a UDP port, using a multicast 
 * source filter
 *
 * Usage: mshow <ip group> <udp port> <filtermode: i | e> *[ip source]
 *
 * File:	mshow.c
 * Date:	26/6/2000
 * Auth:	wilbertdg@hetnet.nl 
 *
 **/

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>

#ifndef WIN32
#include <unistd.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/socket.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <sys/signal.h>
#else
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winerror.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <errno.h>
#define SIOCSIPMSFILTER		SIO_SET_MULTICAST_FILTER
#define SIOCGIPMSFILTER		SIO_GET_MULTICAST_FILTER
#define EADDRNOTAVAIL       WSAEADDRNOTAVAIL
#define isblank(x)			(((x) != ' ') && ((x) != '\t') && ((x) != '\n'))
#endif

/* If the igmpv3 macro IP_MSFILTER_SIZE has been defined, try the source 
 * filter / igmpv3 api
 */
#ifdef IP_MSFILTER_SIZE
#define	MSFILTER
#endif

#define MAX_MSG			1024
#define MAX_SOURCES		100	

#ifndef WIN32
int sockfd;
#else
SOCKET sockfd;
#endif

void catch_term(int); 

/*
 * int main()
 */

int main(int argc, char *argv[])
{
	struct sockaddr_in sa;
	struct hostent *addr; 
	struct ip_mreq mreq;
#ifdef MSFILTER
	struct ip_msfilter *imsfp;
	char buffer[IP_MSFILTER_SIZE(MAX_SOURCES)];
#endif
	struct in_addr ia;
	u_short port;
	int i, nsources, on = 1;
	char *group, msg[MAX_MSG];
	int len, sz, err;

#ifdef WIN32
	/* Initialize WinSock
	 */
	WORD wVersionRequested;
	WSADATA wsaData;
	wVersionRequested = MAKEWORD(2, 2);
	if ((WSAStartup(wVersionRequested, &wsaData)) != 0) {
		printf("failed to initialize winsock\n");
		exit(1);
	}
#endif

	/* Determine options 
	 */
#ifdef MSFILTER
	if (argc < 4) {
#else
	if (argc < 3) {
#endif
		printf("Usage: mshow <group> <port> <filtermode> <sources>\n");
		exit(0);
	}
#ifdef MSFILTER
	imsfp = (struct ip_msfilter*) &buffer;
#endif

	group = argv[1];
	port = (u_short) atoi(argv[2]);
	if (port == 0) {
		printf("Usage: mshow <group> <port> <filtermode> <sources>\n");
		exit(0);
	}

#ifdef MSFILTER
	if (argv[3][0] == 'e')
		imsfp->imsf_fmode = MCAST_EXCLUDE;
	else	
		imsfp->imsf_fmode = MCAST_INCLUDE;
	printf("fmode = %s\n", (imsfp->imsf_fmode == MCAST_INCLUDE) ?
		"include" : "exclude");
	nsources = 0;
	for (i=4; i<argc; i++) {
		imsfp->imsf_slist[nsources].s_addr = inet_addr(argv[i]);
		if (imsfp->imsf_slist[nsources].s_addr == INADDR_NONE) {
			printf("Invalid sources\n");
			exit(0);
		}
		nsources++;
	}
	imsfp->imsf_numsrc = nsources;
#endif

	/* create socket
	 */
#ifndef WIN32
	if (-1 == (sockfd = socket(AF_INET, SOCK_DGRAM, 0))) {
#else
	if (INVALID_SOCKET == (sockfd = socket(AF_INET, SOCK_DGRAM, 0))) {
#endif
		perror("failed to create a socket\n");
	}

	/* determine group
	 */
	if (-1 == (ia.s_addr = inet_addr(group))) {
		if (NULL == (addr = gethostbyname(group))) {
			perror("failed to resolve");
			return(-1);
		}
		memcpy(&ia.s_addr, addr->h_addr_list[0], addr->h_length);
	}

	/* name the socket
	 */
	sa.sin_family = AF_INET;
	sa.sin_port = htons(port);
	sa.sin_addr.s_addr = INADDR_ANY; 
	err = bind(sockfd, (struct sockaddr*) &sa, sizeof(sa));
	if (err == SOCKET_ERROR) {
      printf ("bind() port: %d failed, Err: %d\n", port, WSAGetLastError());
	}

	printf("joining group: %s\n", inet_ntoa(ia));

	/* join the group and set sourcefilter
	 */
	on = 1;
	setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (void*) &on, sizeof(on)); 
#ifndef WIN32
	on = 1;
	setsockopt(sockfd, SOL_SOCKET, SO_REUSEPORT, (void*) &on, sizeof(on)); 
#endif
	mreq.imr_multiaddr.s_addr = ia.s_addr;
	mreq.imr_interface.s_addr = INADDR_ANY;
	if (setsockopt(sockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, 
		(void*) &mreq, sizeof(mreq))) {
		perror("failed to join");
	}

#ifdef MSFILTER
	imsfp->imsf_multiaddr.s_addr = mreq.imr_multiaddr.s_addr;	
	imsfp->imsf_interface.s_addr = mreq.imr_interface.s_addr;
	printf("group  = %s\n", inet_ntoa(imsfp->imsf_multiaddr));
	printf("if     = %s\n", inet_ntoa(imsfp->imsf_interface));
	printf("mode   = %d\n", imsfp->imsf_fmode);
	printf("numsrc = %d\n", imsfp->imsf_numsrc);
	for (i=0; i<imsfp->imsf_numsrc; i++) {
		printf("\t[%d] = %s\n", i, inet_ntoa(imsfp->imsf_slist[i]));
	}
#ifndef WIN32
	if (ioctl(sockfd, SIOCSIPMSFILTER, imsfp) != 0) {
		printf("failed to set sourcefilter: error = %d\n", errno);
	}
#else
	err = WSAIoctl(sockfd, SIO_GET_MULTICAST_FILTER, 
			(PBYTE) imsfp, IP_MSFILTER_SIZE(imsfp->imsf_numsrc), 
			(PBYTE) imsfp, IP_MSFILTER_SIZE(MAX_SOURCES), &sz, NULL, NULL);
	if (err != 0) {
		printf("failed to set sourcefilter: error = %d\n", WSAGetLastError());
	}
#endif
#endif

#ifndef WIN32
    signal(SIGINT, catch_term);
#endif

	while (1) {
		sz = sizeof(sa);
		len = recvfrom(sockfd, msg, sizeof(msg), 0, (struct sockaddr*) &sa, &sz);
		if (len > 0) {
			msg[len] = '\0';
			printf("from %s (%d bytes):\n%s\n", 
				inet_ntoa(sa.sin_addr), len, msg);
		}
		else {
#ifndef WIN32
			printf("failed: %d\n", errno);
#else
			printf("failed: 0x%X (%u)\n", WSAGetLastError(), WSAGetLastError());
#endif
			break;
		}
	}

	/* bye
	 */
#ifndef WIN32
	close(sockfd);
#else
	closesocket(sockfd);
	WSACleanup();
#endif
	return(0);
}

void catch_term(sig_num)
    int sig_num;
{
    printf("terminated.\n");
#ifndef WIN32
	close(sockfd);
#else
	closesocket(sockfd);
#endif
    exit(0);
}